The present invention relates to a method for transporting/storing a wafer, and more particularly to a method for supplying or transporting to manufacturing processes a wafer, namely, a thin plate material, consisting of semiconductor, used as a substrate on which an IC is mounted. The present invention also relates to a transporting material, namely, a wafer carrier to be used to supply or, transport, the wafer to the manufacturing processes or to store the wafer.
The wafer is thin and thus breakable or chippable. The IC is affected in the quality and performance thereof when it is deformed excessively or an internal stress is applied thereto excessively. It is necessary to protect the surface of the wafer from becoming dusty or soiled. If the surface of the wafer is dusty or soiled or has slight damage thereto thereon, circuit having a fine construction cannot be formed.
In this respect, it is necessary to transport and store the wafer with much care so as to avoid the above-described disadvantages.
A known wafer carrier has the following construction. That is, it has a plurality of shelves approximately C-shaped in plan view to hold the periphery of circular wafers each inserted into the space of each C-shaped shelf. Normally, one carrier accommodating 25 wafers is collectively supplied to a necessary manufacturing process.
It is difficult for the conventional wafer carrier to handle wafers separately.
That is, when the specifications of IC chips mounted on the wafer and performances demanded therefor are different from each other, required processing contents of wafers and processing procedures thereof are different from each other. The wafer carrier handling a large number of wafers is incapable of supplying a right wafer to a right processing line or a right processing device. Therefore, wafers are removed from the wafer carrier or inserted thereinto individually.
It takes time and labor to removed a required wafer from the wafer carrier and return a processed wafer thereto in each process. In addition, a device for removing the wafer from the wafer carrier and a device for returning it thereto are complicated in construction. Further, if a wafer is removed from the wrong shelf of the wafer carrier or a processed wafer is returned to the wrong shelf of the wafer carrier and removed therefrom to perform a subsequent processing, a defective product is manufactured. Such a problem does not occur if wafers to be processed in the same manner are accommodated by one wafer carrier. It is very inefficient and uneconomical to accommodate several wafers in the wafer carrier capable of accommodating many more wafers, for example, 25 wafers.